1#include <time.h>
 2#include <limits.h>
 3
 4clock_t clock()
 5{
 6	struct timespec ts;
 7
 8	if (__clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts))
 9		return -1;
10
11	if (ts.tv_sec > LONG_MAX/1000000
12	 || ts.tv_nsec/1000 > LONG_MAX-1000000*ts.tv_sec)
13		return -1;
14
15	return ts.tv_sec*1000000 + ts.tv_nsec/1000;
16}